The appearance of two new pufferfish sightings in Galician waters has reignited scientific concerns about how the ocean is changing in the northwest of the Iberian Peninsula. What just a few decades ago would have seemed an isolated anomaly is now interpreted as yet another symptom of the progressive tropicalization of the marine environment linked to global warming.
A multidisciplinary team led by the Spanish Institute of Oceanography (IEO-CSIC) , with the participation of the Vigo Oceanographic Center, the University of Vigo, the Group for the Study of the Marine Environment (GEMM) and the Aquarium Finisterrae, has documented in detail the presence of the green pufferfish and the land pufferfish on the southern coast of Galicia, specimens that until now were very rare in this part of the Atlantic.
New records of pufferfish in southern Galicia
The study details the capture of two pufferfish specimens in Galician waters , both located in the southern part of the region. The first was a green pufferfish ( Sphoeroides pachygaster ) recorded in 2021 off the Costa da Vela , near O Morrazo, an area frequented by artisanal and purse seine fishing fleets.
The second specimen is a land pufferfish ( Ephippion guttifer ) , located in 2025 in the Pontevedra estuary . According to the team from the Vigo Oceanographic Center, histological analyses performed on this fish revealed that it was a female in the spawning phase , a fact that suggests something more than a simple occasional appearance.
According to the IEO, these findings represent the first documented record of the green pufferfish in Galician waters and the second confirmed record of the land pufferfish in the region. For specialists, the fact that both species have appeared in just a few years and in the same geographical area reinforces the hypothesis of a fundamental change in the ocean's environmental conditions.
The two fish belong to the order Tetraodontiforms, a group that includes the well-known pufferfish, as well de peces moonfish and triggerfish, descendants of a lineage of reef species that originated tens of millions of years ago in tropical and subtropical waters.
Scientific confirmation: from morphology to DNA
The identification of these species was not left to intuition. The IEO team and collaborating entities combined classic morphological analyses with detailed photographic documentation of the specimens to refine the taxonomic determination as much as possible.
Furthermore, the study employed genetic identification using DNA barcoding , a technique that allows for the differentiation of species based on the sequence of a short, standardized fragment of their genome. As explained by Alejandro de Carlos , a researcher at the CIM-University of Vigo , each species leaves its own “genetic signature,” comparable to a commercial barcode that makes it easier to distinguish from others.
The combined use of external morphology, histology, and DNA has allowed for solid confirmation of the presence of the green pufferfish and the land pufferfish in Galicia, minimizing the possibility of identification errors. In the case of the specimen from the Pontevedra estuary, reproductive analysis revealed ovaries in the egg-laying phase, an indicator that these species not only arrive but could also find suitable conditions for reproduction.
According to the authors of the study, the quality and variety of the tests used —including collaboration between different research centers and a scientific aquarium— provides robust support when considering these records as key references in the monitoring of warm-water marine species.
Tetraodontiformes in Spain: increasing diversity
Beyond the two cases detected in Galicia, the study published in the scientific journal Fishes provides the first comprehensive review of Tetraodontiformes diversity in Spanish waters . The current tally places the number of recorded species at 26, belonging to five different families within this order.
The distribution is not homogeneous. According to the review, 22 of these species are found in the Canary archipelagowhere ocean conditions are warmer and more favorable for typically tropical fauna, while 15 species have been cited in the Iberian Peninsula and Balearic IslandsThe Galician coast is located at the northernmost end of that range, so the presence de peces The balloon there is especially significant.
The IEO researcher in Vigo Rafael BañónThe study's lead author emphasizes that growing presence de peces tetraodontiforms in Spanish waters It is already a clear indicator of how the ocean is changing. This type of comprehensive analysis offers an updated picture of a group of species that, until recently, was barely considered in the context of the Iberian Peninsula.
For marine resource managers and conservation officers, having this distribution and diversity map is key when designing monitoring strategies, risk prevention, and adapting fisheries management to a rapidly changing ecological scenario.
Tropicalization of the sea and climate change
The presence of these pufferfish, typical of warm waters, in Galicia is not interpreted as a mere biological anecdote. The authors of the study directly link these sightings to ocean warming and the tropicalization of marine ecosystems in Spain, a phenomenon increasingly documented in the eastern Atlantic and the Mediterranean.
The term “tropicalization” describes the process by which species with tropical or subtropical affinities expand their range to higher latitudes as surface waters warm. On the Iberian Atlantic coast, this shift has already been observed with other fish such as the triggerfish, as well as with certain jellyfish and invertebrate species that were previously rare in Galicia.
According to Bañón, the northward expansion of Tetraodontiformes fits this pattern and provides “further evidence” of the transformation of the Spanish marine environment. The recurring arrival of species of tropical origin poses both a scientific challenge—due to the need to closely monitor their evolution—and a challenge for management, which must adapt to a scenario where biological communities are changing rapidly.
Environmental organizations and marine research groups in Galicia see these findings as a further warning about the effects of climate change on biodiversity in the northwest of the Iberian Peninsula. What was once considered exceptional may be gradually becoming part of the “new normal” for marine ecosystems.
Tetrodotoxin and food safety: a low but monitored risk
One of the most worrying aspects when talking about pufferfish is the possible presence of tetrodotoxin (TTX), one of the most potent known natural neurotoxins. The study notes that certain species de peces balloons can accumulate this toxin in organs such as the liver, gonads or skin, which makes its consumption a serious health risk.
Tetrodotoxin works by blocking sodium channels in nerve and muscle cells , causing symptoms that can range from tingling and numbness to respiratory paralysis. It is a particularly dangerous substance because it is not eliminated by cooking or other conventional cooking methods , and there is currently no specific antidote.
Despite everything, researchers insist that the risk of pufferfish poisoning in Spain is currently low . These species are not commonly found in markets and fishmongers, and their sale is prohibited in the European Union , which drastically reduces the possibility of them reaching consumers' plates.
Fishermen's associations and fish markets have information on these species, and the regulatory framework prevents pufferfish from legally entering the food chain. However, the research team emphasizes that the increase in sightings and records in our waters makes it necessary to strengthen surveillance and improve the identification of potentially toxic specimens , especially in cases of accidental catches or unregulated consumption.
The importance of continuous scientific monitoring
For the IEO and its collaborating centers, the key in the coming years will be to maintain and expand the programs of monitoring of marine species related to climate change. Quickly identify the arrival de peces globe and other tropical organisms allow not only updating biodiversity catalogs, but also anticipate potential food safety problems.
The study emphasizes that a thorough understanding of the composition, geographic distribution, and potential toxicity of marine species is essential for early detection and for alerting the public should specific risks be identified. This monitoring is particularly important in intensive fishing areas and coastal zones where contact between marine life and human activity is more frequent.
Strengthening collaboration between research centers, universities, professional fishers, aquariums, and public administrations is presented as a key element. The accidental catches of unusual species, when well documented and reported, become a valuable source of information for understanding the speed and extent of tropicalization in European seas.
In this context, the two new records de peces The balloons in Galicia function as a kind of "early warning": they indicate that the Iberian Atlantic is changing and that it will be necessary to adapt, both from research and management, to an increasingly warmer and more dynamic marine scenario.
Everything points to the presence of the green pufferfish and the land pufferfish in Galician waters , together with the increase in Tetraodontiformes species in Spain and the toxic potential of some of these fish, having become a palpable indicator of how ocean warming is reshaping marine life in the European environment, forcing us to increase scientific monitoring and take the implications for biodiversity and food security very seriously.
